Film maker Peter Jackson has spoken of his shock and sadness at the drowning of double Oscar-winning Kiwi Michael Hopkins.

Hopkins, 53, drowned while rafting in the Waiohine River in the Tararua Range on Sunday when the inflatable raft he was in was caught in an eddy as the river rose quickly from a flash flood. Hopkins' wife Nicci, and a male friend, who were also on the expedition, survived.

"Myself, along with my fellow producers, Fran Walsh, Philippa Boyens, Caro Cunningham and Zane Weiner, are deeply shocked and saddened to learn of the tragic death of our friend and long time collaborator, Mike Hopkins," Jackson said.

"I know I can speak for the many actors, directors, production and post production crew who were lucky enough to work with Mike, in saying that he will be terribly missed.

"Under his guidance, New Zealand became recognised as one of the leading hubs of post production sound in the world. Beyond that, Mike was a very genuine, caring and warm-hearted guy with a great sense of humour. We are all mourning his passing - his family, his friends and colleagues are in our thoughts," Jackson said.

Hopkins was an in-demand sound editor who had worked with Jackson on his films Braindead, The Frighteners, Heavenly Creatures, the Lord of the Rings trilogy and King Kong. He also worked on Hollywood hits Transformers, Dreamgirls, Kung Fu Panda and Valkyrie.

He and American Ethan Van der Ryn won sound editing Oscars for their work on The Two Towers in 2003 and King Kong in 2006.

Hopkins grew up in the South Island, then moved to Wellington and, more recently, Wairarapa.

Kiwi film director Geoff Murphy, who first with Hopkins on Never Say Die in 1988 and had been working closely with him during the past six months on a remastering of the 1983 film Utu, said Hopkins was a "frontrunner" in the movie industry.

"He was one of those guys who was at the very forefront of technology and knew exactly what was going on," Murphy said.

Producer Dave Gibson said Hopkins had been looking forward to spending more time in New Zealand after a few years of routinely being called to Hollywood. He had bought a lifestyle block in Greytown and planned to enjoy it on a more regular basis with his wife, whom he married about a year ago.

"He got work because he was very, very good at what he did. He was also a lovely guy. I'm sure everyone who worked with him would say that," Gibson said.

The man who saved Hopkins' wife from the river said the rafters were extremely unlucky. Had they launched just 30 minutes earlier, they would have been safe, river contractor Bruce Slater said. Thirty minutes later and they would have seen the river was too high.

Instead they were caught in a torrent in the Waiohine Gorge, moving at up to 50kmh and with crushing 1.5-metre waves.

Slater, who monitors the river every day, said the water level rose rapidly while the party was in the water.

"It shot up two to three metres and the flow - which would've been 10 cubic metres - shot up to 300 cubic metres. So that's huge volume."

The three rafters were wearing life jackets, wetsuits and helmets.

Hopkins' family are holding a celebration of his life in Greytown on Thursday.